(SMTP) support DATA better in the server and make sure to "escape" CRLF.CRLF

sequences in uploaded data. The test server doesn't "decode" escaped dot-lines
but instead test cases must be written to take them into account. Added test
case 803 to verify dot-escaping.

lib/smtp.c

@@ -639,6 +639,7 @@ static CURLcode smtp_done(struct connectdata *conn, CURLcode status,
   struct SessionHandle *data = conn->data;
   struct FTP *smtp = data->state.proto.smtp;
   CURLcode result=CURLE_OK;
+  ssize_t bytes_written;
   (void)premature;
 
   if(!smtp)
@@ -653,6 +654,15 @@ static CURLcode smtp_done(struct connectdata *conn, CURLcode status,
     conn->bits.close = TRUE; /* marked for closure */
     result = status;      /* use the already set error code */
   }
+  else
+    /* TODO: make this work even when the socket is EWOULDBLOCK in this call! */
+
+    /* write to socket (send away data) */
+    result = Curl_write(conn,
+                        conn->writesockfd,  /* socket to send to */
+                        SMTP_EOB,           /* buffer pointer */
+                        SMTP_EOB_LEN,       /* buffer size */
+                        &bytes_written);    /* actually sent away */
 
   /* clear these for next connection */
   smtp->transfer = FTPTRANSFER_BODY;

lib/smtp.h

@@ -58,4 +58,8 @@ extern const struct Curl_handler Curl_handler_smtps;
 #define SMTP_EOB "\x0d\x0a\x2e\x0d\x0a"
 #define SMTP_EOB_LEN 5
 
+/* if found in data, replace it with this string instead */
+#define SMTP_EOB_REPL "\x0d\x0a\x2e\x2e"
+#define SMTP_EOB_REPL_LEN 4
+
 #endif /* __SMTP_H */

lib/transfer.c

@@ -784,6 +784,68 @@ static CURLcode readwrite_upload(struct SessionHandle *data,
       /* store number of bytes available for upload */
       data->req.upload_present = nread;
 
+#ifndef CURL_DISABLE_SMTP
+      if(conn->protocol & PROT_SMTP) {
+        /* When sending SMTP payload, we must detect CRLF.CRLF sequences in
+         * the data and make sure it is sent as CRLF..CRLF instead, as
+         * otherwise it will wrongly be detected as end of data by the server.
+         */
+        struct smtp_conn *smtpc = &conn->proto.smtpc;
+
+        if(data->state.scratch == NULL)
+          data->state.scratch = malloc(2*BUFSIZE);
+        if(data->state.scratch == NULL) {
+          failf (data, "Failed to alloc scratch buffer!");
+          return CURLE_OUT_OF_MEMORY;
+        }
+        /* This loop can be improved by some kind of Boyer-Moore style of
+           approach but that is saved for later... */
+        for(i = 0, si = 0; i < nread; i++, si++) {
+          int left = nread - i;
+
+          if(left>= (SMTP_EOB_LEN-smtpc->eob)) {
+            if(!memcmp(SMTP_EOB+smtpc->eob, &data->req.upload_fromhere[i],
+                       SMTP_EOB_LEN-smtpc->eob)) {
+              /* It matched, copy the replacement data to the target buffer
+                 instead. Note that the replacement does not contain the
+                 trailing CRLF but we instead continue to match on that one
+                 to deal with repeated sequences. Like CRLF.CRLF.CRLF etc
+              */
+              memcpy(&data->state.scratch[si], SMTP_EOB_REPL,
+                     SMTP_EOB_REPL_LEN);
+              si+=SMTP_EOB_REPL_LEN-1; /* minus one since the for() increments
+                                          it */
+              i+=SMTP_EOB_LEN-smtpc->eob-1-2;
+              smtpc->eob = 0; /* start over */
+              continue;
+            }
+          }
+          else if(!memcmp(SMTP_EOB+smtpc->eob, &data->req.upload_fromhere[i],
+                          left)) {
+            /* the last piece of the data matches the EOB so we can't send that
+               until we know the rest of it */
+            smtpc->eob += left;
+            break;
+          }
+
+          data->state.scratch[si] = data->req.upload_fromhere[i];
+        } /* for() */
+
+        if(si != nread) {
+          /* only use the new buffer if we replaced something */
+          nread = si;
+
+          /* upload from the new (replaced) buffer instead */
+          data->req.upload_fromhere = data->state.scratch;
+
+          /* set the new amount too */
+          data->req.upload_present = nread;
+        }
+
+      }
+      else
+#endif /* CURL_DISABLE_SMTP */
+
       /* convert LF to CRLF if so asked */
       if((!sending_http_headers) &&
 #ifdef CURL_DO_LINEEND_CONV
@@ -837,10 +899,10 @@ static CURLcode readwrite_upload(struct SessionHandle *data,
 
     /* write to socket (send away data) */
     result = Curl_write(conn,
-                        conn->writesockfd,     /* socket to send to */
+                        conn->writesockfd,         /* socket to send to */
                         data->req.upload_fromhere, /* buffer pointer */
                         data->req.upload_present,  /* buffer size */
-                        &bytes_written);       /* actually send away */
+                        &bytes_written);           /* actually sent */
 
     if(result)
       return result;